German Published Application (Auslegeschrift) DT-AS 1 905 462 describes a roller bearing for jet power plants, i.e. jet engines or turbines, in which the bore surface of the inner race ring is provided with axially extending grooves which serve to conduct lubricant and as cooling channels. The lubricant thus flows beneath the bearing and can be passed through radial bores to the active surfaces of the bearing to be lubricated.
Since jet engines operate at high angular velocities and temperatures, high centrifugal forces and thermal-expansion forces arise, the bearing being very firmly shrunk onto the shaft.
It has been found that with rings with axially extending lubricating grooves, of the type described in the aforementioned publication, the centrifugal forces and shrinkage stresses impart an undulating characteristic to the active running surface of the bearing-race ring.
Since the cross-section of the axially grooved bearing ring subject to tension is not constant, there arise at the groove locations elastic flattenings which affect the useful life of the bearing highly detrimentally, especially since the roller bodies and race surfaces wear quite rapidly.
Furthermore, such race rings produce vibrations and noise which are disadvantageous and the fabrication of the axially extending grooves presents an expensive machine process which is also time-consuming.